Fuse plug



July 26, 1938.

.J. CORSER FUSE PLUG Original Filed March 5, 1936 Patented July 26, 1938 UNITED STATES PATENT OFFICE Application March 5,

1936, Serial No. 67,392

Renewed July 30, 1937 20 Claims.

This invention relates to fuse plugs of that type adapted to be screwed into sockets. Such plugs usually have been provided with fuses located back of mica disks. They have been objec- 5 tionable because the mica has added to the cost; because it is diiicult to see the fuses through the mica; and because the plugs can be reinserted, when burned out, with coins or other metallic objects inserted to bridge the fuse.

An object of the present invention is to eliminate the mica and to provide a means whereby, when the fuse is burned out, it will not fit the socket, thus positively indicating to the user that the fuse is useless and a new plug must be used.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter n incre fully described and pointed out in the '0 claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of lthe invention as claimed. Q In the accompanying drawing the preferred forms of the invention have been shown.

In said drawing:

Figure l is a central section taken longitudinally through the plug.

Figure 2 is a side elevation.

Figure 3 is a section on line 3-3, Figure l.

Figure 4 is a view similar to Figure l showing a modied construction.

Figure 5 is a side elevation thereof.

Figure 6 is a section through another form.

Referring to the figures by characters of reference, I designates a plug of porcelain or other suitable insulating material having a radial slot 2 extending thereinto from one end and intersected at its outer side by a groove 3 extending partly around the plug.

A sleeve 4 of conductive material is tted on the plug and is screw-threaded so as to engage properly in the usual socket. This sleeve is slotted at 5 to form a tongue 6 extending longitudinally of groove 3 and interrupting the thread on the sleeve. As the sleeve is oi resilient material the tongue is likewise resilient.

A contact I is located at the center of one end oi the plug I and is formed on one end of an anchoring strip which is also a conductor. This strip is tted in the plug I at the inner end of slot 2 and is joined to the tongue 6 by the fuse 9. Thus the tongue is held normally retracted back in groove 3 as shown.

(Cl. 20G- 2130) The plug is adapted to be inserted irrto a fuse receptacle or socket in the usual way. When the fuse is burned out it releases the tongue 6. Therefore, when the plug is removed for inspection the released tongue will spring out of the groove 3 as shown by broken lines in Figure 3 and indicate to the user that the fuse is useless. It will also act as a baille to prevent the plug from being reinserted into the receptacle for the purpose of holding a coin or the like in position.

In Figures 4 and 5 the plug Ii) has been shown with its threaded sleeve II slotted at I2 to provide a tongue I3 extending along a longitudinal groove I4 in the plug. This tongue is also held normally under restraint by a fuse l5 joined to a conductor I6 in the plug and leading from contact II.

In this modified structure the operation is the same as that heretofore described. When the fuse is burned it releases the tongue I3 which is thus free to spring outwardly as shown by broken lines in Figure 4, thus to form a baffle.

In Figure 6 the plug I 8 has a diametrical opening I9 and a radial recess 2D both opening into a longitudinal groove 2 I. The threaded sleeve 22 on the plug has an opening 23 alined with recess 20 and is also formed with an inwardly extended ear 24 overhanging the opening. This ear supports a tongue 25 which laps a ange 26 on a plunger 2l.

The plunger is seated in recess 2U and a spring 28 n is also located in said recess:

A Contact 29 is located at one end of the plug and is held in place by a combined conductor and anchoring strip 30 seated in the plug. A fuse 3| connects this strip to the tongue 25 and the tongue, in turn, holds the plunger normally pressed back into recess 2U so as to maintain the spring under compression.

When the fuse is burned it releases tongue 25 ,f

Thus reinsertion of the plug into the receptacle is prevented.

What is claimed is: l. A plug, a fuse, and means released by the fuse when burned for preventing insertion of the plug into a receptacle.

2. A fuse plug for insertion into a fuse receptacle before the fuse is burned and removable from the receptacle before or after the fuse is burned, said fuse plug comprising a plug, a baille movable laterally to position beyond the plug, and a fuse for holding the baille normally retracted into the plug.

3. A plug, a sleeve thereon, a contact, a baille movably mounted relative to the sleeve, and a fuse connection between the contact and baille for holding the baille normally retracted into the sleeve and plug.

4. A plug, a sleeve thereon, a baille carried by the sleeve and mounted to spring outwardly relative thereto when unrestrained, and a fuse for holding the baille against movement.

5. A plug, a sleeve thereon, a resilient baille carried by the sleeve and mounted to spring outwardly relative thereto when unrestrained, and a fuse for holding the baille under restraint.

6. A plug, a threaded sleeve thereon, a resilient baille carried by the sleeve and extending partly therearound, said baille being mounted to spring outwardly relative to the sleeve when unrestrained, and a fuse in the plug for holding the baille under restraint. Y

7. A plug, a threaded sleeve thereon, a resilient baille carried by the sleeve and interrupting the thread, said baille being mounted to spring outwardly relative to the sleeve when unrestrained, and a fuse in the plug for holding the baille under restraint.

8. A plug, an apertured sleeve thereon, a spring actuated plunger in the plug, and fuse restrained means for holding the plunger normally retracted in the plug, said plunger when released being movable into the aperture and outwardly from the sleeve.

9. A plug, a fuse therein, and means coni trolled by the fuse for preventing insertion of the plug into a receptacle when said fuse has burned.

10. A plug, a fuse therein, and spring means released by the fuse when burned for thereafter preventing insertion of the plug into a receptacle.

11. A plug, a fuse therein and spring controlled means released by the fuse when burned for preventing insertion of the plug into a receptacle.

12. A plug fuse adapted for insertion in a fuse receptacle and including a fuse and noncurrent carrying means normally retracted into the plug and adapted to be released by the fuse when burned for preventing insertion of the plug into a receptacle.

13. A plug fuse adapted to be inserted in a fuse Vreceptacle and including a plug body, a fuse therein and normally non-current-carrying means controlled by the fuse for preventing insertion of the fuse into a receptacle after burning of the fuse.

14. A plug fuse adapted to be inserted in a fuse receptacle and including a plug body, a fuse therein and non-current carrying means controlled by the fuse for preventing insertion of the fuse into a receptacle after burning of the fuse.

15. A plug fuse adapted for insertion into a fuse receptacle and including a plug body, a fuse and means biased to extend beyond the periphery of the plug body adapted to prevent insertion of the plug into a plug receptacle and normally held by the fuse within the periphery of the plug body.

16. A plug fuse adapted for insertion into a fuse receptacle and including a fuse and means controlled by movement of at least a part of said fuse when burned for thereafter preventing insertion of the plug into a receptacle.

17. A plug fuse adapted for insertion into a receptacle and comprising a plug body, a fuse supported thereby and fuse-controlled normally ineilective means adapted to prevent insertion of a plug fuse into a receptacle, said means being rendered effective on burning of the fuse.

18. A circuit protector comprising a plug body, a circuit opening means therein having a portion thereof adapted to be moved during circuitopening operation thereof and a baille biased to have a portion thereof project beyond the external periphery of the plug body to prevent insertion of the protector Vinto a receptacle and normally restrained within the periphery of the plug body by the circuit opening means.

19. A plug fuse adapted for insertion into a receptacle and comprising a plug body, a fuse therein and normally-ineffective means for preventing insertion of a plug fuse into a receptacle said means becoming effective on removal of a burned out plug fuse from a receptacle.

20. A plug fuse as set forth in claim 10 in which said spring means comprises a part of the current-traversed elements of the plug fuse.

JOHN CORSER. 

